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In this paper, the vibration model of the piezoelectric cantilever, the piezoelectric and electromagnetic output model are established. The simulation analysis of the cantilever vibration is performed using Comsol Multiphysics software. The effects of structural parameters, including cantilever length, cantilever thickness, piezoelectric layer length, piezoelectric layer thickness, coil size and position, on the resonance frequency and output voltage were analyzed. A cantilever vibration energy collection device is designed. The feasibility and accuracy of theoretical analysis were verified through the experiment, and the resonance frequency and the output voltage of the experiment basically agree with the theoretical calculation value. [ABSTRACT FROM AUTHOR]

This paper studies the vibration detection technique based on the piezoelectric cantilever structure, and analyzes the relationship between the resonance frequency and the structure parameters. Although the output of the electrical signal is too small, it can be used to detect vibration during resonance with the maximum output voltage. A vibration testing device is designed based on piezoelectric cantilever structure, because in the vibration environment of the same frequency the vibration detection technology can obtain larger electrical signals. It can realize the automatic detection of real-time vibration state, and the vibration energy can charge the power supply through the energy storage circuit. Through the experimental method to verify relationship between the output voltage of piezoelectric cantilever beam, mass block, piezoelectric cantilever structure parameters and frequency, the experimental value of resonance frequency is very close with theoretical calculation value. The experimental resonant frequency of the designed piezoelectric cantilever beam is 16.5 Hz, which is slightly lower than the theoretical value of resonant frequency of 17.6 Hz, and the peak value of the piezoelectric output open-circuit voltage is 7.1 V. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the occurrence and risk factors of acute kidney injury (AKI) in ventilated newborns. Methods: In total, 139 newborns receiving mechanical ventilation (MV) were reviewed in this retrospective study. The demographic and clinical data were collected. Then, the independent risk factors for AKI were evaluated using univariate and multivariate logistic regression analyses. Results: The incidence rate of AKI was 15.11% (21/139) in ventilated newborns. Univariate analysis showed significant differences in gestational age, birth weight, Apagar scores, the highest oxygen concentration, serum creatinine levels at admission and 48 h after MV, history of asphyxia, urine output at 48 h after MV, invasive MV, noninvasive MV, and outcomes between AKI and non-AKI groups (all p <.05). The lower gestational age (odd ratio (OR): 1.194, 95% confidence interval (CI): 1.013–1.407, p =.035), the increased use of invasive mechanical ventilation (IMV) (OR: 4.790, 95% CI: 1.115–20.575, p =.035), and lower birth weight (OR: 0.377, 95% CI: 0.178–0.801, p =.011) were independent risk factors for the occurrence of AKI. Additionally, higher stage of AKI was significantly associated with poor prognosis of AKI (p =.018). Conclusion: In this retrospective study, it was found that lower gestational age, birth weight, and increased use of IMV were independent risk factors for AKI in ventilated newborns. The poor prognosis might be indicated by the higher AKI stage. [ABSTRACT FROM AUTHOR]